1. Field of the Invention
The invention relates to a seal arrangement consisting of two abutting structural parts made of concrete, steel, reinforced concrete, cast iron, or other materials (e.g. synthetic resins), as well as of a sealing section made of elastomeric material (i.e., rubber or rubber-like material), which bridges and seals the gap between the two structural parts, whereby the structural parts particularly are segments assembled to form a tubular tunnel with the formation of transverse and longitudinal joints, whereby each segment preferably is provided with at least one peripheral recess covering all the mating sides of the segment, and whereby a sealing section extending in the form of a strand is present in each recess, such sealing section being provided particularly with grooves extending in the form of strands, such grooves being arranged on the base side of the sealing section, and/or with channels extending in the form of strands as well, forming a sealing frame with frame corners. As the segments have four mating sides in most cases, the sealing frame consists of four assembled-sealing sections, whereby the corners of the frame are preferably manufactured by the injection molding process.
2. The Prior Art
A seal arrangement according to the above type is known, for example from U.S. Pat. No. 4,946,309. Due to the compression of the abutting structural parts or segments with reduction of the spacing of the gap or transverse and longitudinal joints, the sealing section made of elastomeric material develops its sealing capacity under the interaction of force and reactive force. Such compression seals are successfully used in connection with numerous tunnel projects.
For the purpose of additional pressure activation, it has been proposed, furthermore, to provide a sealing section toward the water side with a lateral bore, which is connected with at least one of the channels extending in the form of strands (U.S. Pat. No. 5,044,823). When water penetrates from the outer side of the segment, the channel or the channels is/are supported by the water pressure, which leads to an increase in the sealing capacity. However, the drawback is that the bore may be closed due to soiling, resulting in inefficiency of said additional pressure-activating measure.
Furthermore, a seal arrangement is introduced in EP-B-0 340 659, in which the sealing section has a hollow space connected with an injection channel. The sealing section is activated by means or an injectable medium increasing the total volume. In this way, a high sealing effect is obtained without requiring compression of the sealing sections during assembly. However, the drawback in this connection is that an injection channel has to be made available, which, furthermore, frequently has to be extended through the segments, and that additional device parts are needed.
French laid-open patent specifications 2 669 259, 2 678 680, and 2 712 655 introduce seal arrangements in which the back of the sealing section has at least one groove extending in the form of a strand, for which provision is made for the purpose of receiving an emergency seal, in particular an activatable, and especially a water-activatable sealing material. Here, the back of the sealing section may have one single groove. Another possibility is to fit the back of the sealing section with two grooves, which are arranged substantially mirror-symmetrically relative to each other based on the vertical plane of the center of the section (EP-A-0 522 912).
In spite of numerous solutions proposed for sealing abutting structural parts, the problem has not been solved adequately heretofore. Structural parts, especially tunnel segments, may change in their positions relative to each other in the course of time (e.g. due to the action of conditions caused by geological changes), for example due to ovalizing, so that gaps open up. Moreover, structural parts or tunnel segments may be dislocated with displacement when installed. Such constellations then necessarily lead to a negative influence on the sealing efficiency of the sealing section.